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This study investigates the presence, distribution, and potential impacts of perfluoroalkyl substances (PFASs) and hexabromocyclododecanes (HBCDs) on the Antarctic marine environment. The analysis results from the King Sejong Station, the Jang Bogo Station, and Cape Evans revealed the highest concentrations of both PFASs and HBCDs at King Sejong Station, indicating the significant influence of human activity. Short-chain perfluorocarboxylic acids (PFCAs) dominated the seawater samples, with PFPeA at the highest concentration (0.076 ng/L) at King Sejong Station, whereas perfluorosulfonic acids (PFSAs) were prevalent in the sediments, with PFHxS reaching 0.985 ng/g. Total PFASs in benthos ranged from N.D. to 2.40 ng/g ww across all stations. This indicated the effects of long-range transport and glacial meltwater. α-HBCD was the most common diastereomer in benthos samples, detected in 58.3% of samples, suggesting its selective persistency. Although risk quotient analysis revealed low immediate risks to lower-trophic organisms, potential risks remain owing to their persistence and bioaccumulation potential. Contaminant patterns changed after regulations: perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) levels decreased, unregulated PFASs increased, HBCD stereoisomer ratios shifted towards α-HBCD dominance, and overall HBCD concentrations declined. Widespread persistence of regulated substances was observed in Antarctic environments, highlighting the need for comprehensive and long-term monitoring strategies. This study provides essential baseline data on contaminant distributions across the Southern Ocean, contributing to our understanding of emerging pollutants in Antarctic regions and informing future environmental protection efforts. [Display omitted] • Highest PFAS and HBCD levels at King Sejong Station show human activity's impact on Antarctica. • Short-chain PFCAs dominated seawater, indicating long-range transport and glacial melt influence. • α-HBCD predominated in benthos due to bioaccumulation and long-range atmospheric transport. • Risk quotient analysis showed low immediate risk, but long-term ecosystem health concerns persist. [ABSTRACT FROM AUTHOR]

The phylogroup Chloromonadinia (Volvocales, Chlorophyceae) comprises green microalgae that inhabit a variety of environments, including freshwater, soil, and snow. Two strains were isolated from two sites in the South Shetland Islands in maritime Antarctica, and their morphological and molecular characteristics were studied. Light microscopy of the strain KSF0090 revealed ellipsoidal or broad ellipsoidal, sometimes almost spherical cells with a chloroplast without a pyrenoid, a prominent eyespot, and a hemispherical papilla. The vegetative cells of KSF0208 were ellipsoidal to ovoid cells with a chloroplast with a central pyrenoid, a linear eyespot, and a papilla. The two strains differed from other closely related species based on size and the aforementioned morphological characteristics. Nuclear small subunit rDNA sequence data indicated that each strain formed a distinct well-supported lineage within the phylogroup Chloromonadinia. In addition, comparative analyses of the secondary structures of internal transcribed spacer 2 and compensatory base changes were used to identify and characterize the two strains. Based on their morphological and molecular characteristics, we propose KSF0090 and KSF0208 as two new species, Chloromonas deceptionensis sp. nov. and Ostravamonas greenwichensis sp. nov., respectively. [ABSTRACT FROM AUTHOR]

The community structure and assemblages of marine benthic organisms were investigated in coastal areas near the Jang Bogo Antarctic Research Station in Terra Nova Bay during the 2012–2018 summer seasons. We also examined the recovery pattern of marine benthic organisms following disturbance due to the construction of the Jang Bogo Station. A total of 26 taxa were identified in the study area during the experimental period. Species number and diversity indices (richness, evenness, and diversity) were relatively low compared to data previously reported from Terra Nova Bay. Sphaerotylus antarcticus, Clavularia frankliniana, Hydractinia sp., Iridaea cordata, Fragilariopsis spp., Alcyonium antarcticum, and Metalaeospira pixelli were the dominant species in this area. Of these, the diatom Fragilariopsis spp. were the most abundant species, indicating their key role in maintaining the marine benthic community and controlling biogeochemical cycling. During the construction of the Jang Bogo Station, sediment coverage increased and diatoms declined due to the release of sediment into the coastal area. In February 2014, one month after the disturbance due to cyclone, the diatom coverage increased dramatically and thereby species number, richness index, and diversity index steadily rose from 2015 to 2018. However, non-metric multidimensional scaling ordination analysis of species similarities among sampling times showed that community structure had not completely recovered by 2018. Thus, long-term monitoring is required to elucidate the post-disturbance settlement mechanisms of marine benthic organisms at the study area in Terra Nova Bay. [ABSTRACT FROM AUTHOR]

Native biodiversity and ecosystems of Antarctica safeguarded from biological invasion face recent threats from non-native species, accelerated by increasing human activities and climate changes. Over two decades ago, the winter crane fly, Trichocera maculipennis , was first detected on King George Island. It has now successfully colonized several research stations across King George Island. To understand the origin, genetic diversity, and population structure of this Holarctic species, we conducted mitochondrial DNA cytochrome c oxidase subunit I (COI) sequence analysis across both its native and invasive ranges. In parallel, we performed microsatellite loci analysis within the invasive ranges, utilizing 12 polymorphic microsatellite markers. Furthermore, we compared body sizes among adult males and females collected from three different locations of King George Island. Our COI sequence analysis exhibited two different lineages present on King George Island. Lineage I was linked to Arctic Svalbard and Polish cave populations and Lineage II was related to Canadian Terra Nova National Park populations, implying multiple origins. Microsatellite analysis further exhibited high levels of genetic diversity and significant levels of genetic differentiation among invasive populations. Body sizes of adult T. maculipennis were significantly different among invasive populations but were not attributed to genetics. This significant genetic diversity likely facilitated the rapid colonization and establishment of T. maculipennis on King George Island, contributing to their successful invasion. Molecular analysis results revealed a substantial amount of genetic variation within invasive populations, which can serve as management units for invasive species control. Furthermore, the genetic markers we developed in the study will be invaluable tools for tracking impending invasion events and the travel routes of new individuals. Taken together, these findings illustrate the highly invasive and adaptable characteristics of T. maculipennis. Therefore, immediate action is necessary to mitigate their ongoing invasion and facilitate their eradication. • COI sequences show two different lineages present on King George Island. • Lineage I and Lineage II were related to Arctic and North America, respectively. • Multiple origins of Trichocera maculipennis on King George Island. • High levels of genetic diversity and significant levels of genetic differentiation. • Body sizes of adult were significantly different among populations. [ABSTRACT FROM AUTHOR]